Short-term effects of brimonidine/timolol and dorzolamide/timolol on ocular perfusion pressure and blood flow in glaucoma

Introduction: To examine the comparative short-term effects of brimonidine/timolol and dorzolamide/timolol on ocular perfusion pressure and retrobulbar blood flow in patients with primary open angle glaucoma (OAG). Methods: In a prospective, randomized, double-blind, crossover study, intraocular pressure (IOP), blood pressure (BP), ocular perfusion pressure (OPP), and retrobulbar hemodynamics were assessed in 15 patients with OAG (mean age 68.1 years, eight women) with well controlled IOP. IOP was measured by Goldman applanation tonometery and color Doppler imaging was utilized to assess the retrobulbar blood vessels before and 1 month after treatment with topical brimonidine/timolol and dorzolamide/timolol. Statistical analysis was performed by Friedman two-way analysis of variance by ranks and post-hoc Wilcoxon signed rank test for multiple comparisons with Holm's sequential Bonferroni procedure. P values <0.05 were considered statistically significant. Results: The Friedman test and subsequent post-hoc analysis indicated that IOP, BP, OPP, and retrobulbar blood flow velocities did not significantly differ between brimonidine/timolol and dorzolamide/timolol after 1-month treatment administration in patients with OAG and well controlled IOP. Conclusion: In this cohort of patients with OAG, short-term treatment with brimonidine/timolol and dorzolamide/timolol results in similar effects on OPP and retrobulbar blood flow velocities.